To meet the increased demand for wireless data traffic since the deployment of 4G communication systems, efforts have been made to develop an improved 5G or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a “Beyond 4G Network” or a “Post LTE System”.
Implementation of the 5G communication system in higher frequency (mmWave) bands, e.g., 60 GHz bands, is being considered in order to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission distance, beamforming, massive multiple-input multiple-output (MIMO), Full Dimensional MIMO (FD-MIMO), array antenna, analog beam forming, and large scale antenna techniques are being discussed for the 5G communication system.
In addition, in the 5G communication system, there are developments under way for system network improvement based on advanced small cells, cloud Radio Access Networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), reception-end interference cancellation, and the like.
In the 5G system, Hybrid FSK and QAM Modulation (FOAM) and sliding window superposition coding (SWSC) as advanced coding modulation (ACM) and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SOMA) as advanced access technology have been developed.
The Internet, which is a human centered connectivity network where humans generate and consume information, is now evolving into the Internet of Things (IoT) where distributed entities, such as things, exchange and process information without human intervention. The Internet of Everything (IoE), which is a combination of IoT technology and Big Data processing technology through connection with a cloud server, has emerged.
As technology elements, such as “sensing technology”, “wired/wireless communication and network infrastructure”, “service interface technology”, and “security technology” have been demanded for IoT implementation, there has been recent research into a sensor network, Machine-to-Machine (M2M) communication, Machine Type Communication (MTC), and so forth.
Such an IoT environment may provide intelligent Internet technology services that create new values for human life by collecting and analyzing data generated among connected things. The IoT may be applied to a variety of fields including smart home, smart building, smart city, smart car or connected cars, smart grid, health care, smart appliances, and advanced medical services through convergence and combination between existing Information Technology (IT) and various industrial applications.
In line with these developments, various attempts have been made to apply the 5G communication system to IoT networks. For example, technologies such as a sensor network, Machine Type Communication (MTC), and Machine-to-Machine (M2M) communication may be implemented by beamforming, MIMO, and array antennas. Application of a cloud Radio Access Network (RAN) as the above-described Big Data processing technology may also be considered to be an example of convergence between the 5G technology and the IoT technology.
In a wireless communication system such as the LTE/LTE-A system, a base station estimates an uplink channel based on a reference signal such as a sounding reference signal (SRS) transmitted by a terminal, determines precoding information and modulation and coding scheme (MCS) information, and transmits the determined information to the terminal. The terminal receives the precoding and MCS information via uplink (UL) downlink control information (DCI) and performs uplink transmission based on the received information. The UL DCI is restricted in capacity for certain reasons such as sufficient coverage acquisition, thereby preventing a large amount of information from being transmitted. In this respect, the legacy wireless communication systems support only wideband precoding based on single precoding information transmission.
However, wideband precoding is inferior in precoding accuracy to subband precoding, and the uplink transmission efficiency difference between wideband precoding and subband precoding increases in proportion to the number of transmit antennas of the terminal. In comparison with the current wireless communication system designed under the assumption of up to 4 transmit antennas per terminal, next generation wireless communication (e.g., 5G new radio (NR)) systems are likely to support 4 or more transmit antennas at the terminal by considering enhancement in antenna form factor and development of radio frequency (RF) technologies along with the employment of high frequency carriers. There is therefore a growing need to support uplink subband precoding in the NR communication systems.